Method of shrinking and felting animal fibers



Patented Sept. 10, 1929.

UNITED STATES PATENT OFFICE.

METHOD OF SHRINKING AND FEL'IING ANIMAL FIBERS.

No Drawing. Application filed February 7, 1928,

In the treatment of animal fibers, such as fur, hair or wool, in which the fibers are shrunken and felted together, as for example in the manufacture of felt hats, the

fibers, after having been subjected to a preliquor which may be, for example, pure water or water slightly acidulated. It has been proposed heretofore to promote the shrinking and felting by the addition to the liquor in the presence of which the operation is carried on of a relatively small quantity of a bisulphite. The use of bisulphites, however, has not proved to be wholly satisfactory in practice for the reason that bisulphites have a tendency to soften the fibers, and sometimes to have an unfavorable action on the dyestuffs employed, and generally to have a. deleterious effect upon the workmen as well as upon the metal parts of the apparatus emp oyed by reason of decomposition of the bisulphites in hot solutions and the release of free sulphur dioxide fumes.

In accordance with the present invention, however, it has been found that the undesirable effects of bisulphites are overcome and the process of felting the fibers is promoted by the use of a condensation product of sulphur dioxide or a bisulphite with an aldehyde, such, for example, as formaldehyde. In the practice of the method the sulphur dioxide or a bisulphite is condensed with an aldehyde, such as formaldehyde, in the manner well known to chemists of producing a condensation product, and of such condensation product a quantity which may vary somewhat with the nature of the fiber to be felted, or with its intended use, but is rela tively small as compared by weight with the weight of the fiber under treatment, is added to the liquor in the presence of which the shrinking and felting operation is carried on in the usual manner. It is found that the resultant felt is considerably smoother and tighter when treated in this manner than is the case if the same material is treated without the condensation product. Further- Serial No. 252,685. Renewed January 31, 1929.

more, the condensation product has no un-- favorable effect upon the color, which oftentimes is brightened considerably and appears. to be faster to light. deleterious fumes does not occur.

It has been found that the use of bisulphite leads to a wasting of the substance of the fibers and that the use of a condensation product, as described, inhibits the hydrolysis of the fibers and prevents such wasting of their substance.

The use of a condensation product of sulphur dioxide with an aldehyde is claimed in a separate application filed concurrently herewith.

I claim as my invention:

1. The improvement in the method of shrinking and felting animal fibers in the presence of a liquor which consists in the addition to such liquor of the condensation product of a bisulphite with an aldehyde.

2. The improvement in the method of shrinking and felting animal fibers in the presence of a liquor which consists in the addition to such liquor of the condensation product of a bisulphite with formaldehyde. This specification signed this 3d day of February A. D. 1928.

JOHN H. MARTIN.

Again, the release 01' 

